Mapping Destination signs on US Motorways

[pratikyadav]

Imagery source- Mapillary

Task Objective

To add destination=* and destination:ref=* tags on motorway_link ways representing the guidance signboard using Checkautopista2.

Background

destination=* tag is used to represent the city/town/neighborhood/road that you can reach by switching to the concerned highway. destination:ref=* tag is used to signifies the motorway number (ref tag of motorway) that is used to reach the destination. These tags are added on ways and not nodes and thus considered more relevant for navigation purpose when compared to exit_to tag used on motorway_junction node

Currently in the US, there are 25446 ways with destination=* tag and 13030 ways with destination:ref=* tag (as on 30 March 2016). All exit numbers junctions lead to at least 1 destination with 52,000 exit numbers in the US. This accounts minimum of about 25,000 missing destination=* and 39,000 missing destination:ref=* tag in the US.

• Map of currently mapped destination tags(red lines)
• Map of currently mapped destination:ref tags (blue lines)

Focus area

The 9 States used in exit number mapping are taken as focus area based on mapillary coverage, as it is the primary source.

• California
• Florida
• New Jersey
• Maryland + DC
• Pennsylvania
• Washington State
• Colorado
• Texas
• Illinois

Mapping Workflow

Gist for detailed workflow

Other tags

Other than destination, exit_to tag is prominently used to represent guidance signboards(see taginfo). For now, we will be only adding missing destination and destination:ref tag to motorways that don't have related exit_to tag, as adding both destination and exit_to to the same way will be redundant work and could be solved with an automated approach later.

Changeset comment and source

Comment-> Adding missing destination tags https://github.com/mapbox/mapping/issues/169
Source-> Bing;Mapillary;Wikipedia

Team

@mapbox/team-data

Progress

• Daily Stats
  The current estimate is ~4 weeks for 9 states.

Resources

• Mapillary coverage layer - click this link to load in JOSM
  tms:http://d2munx5tg0hw47.cloudfront.net/tiles/{zoom}/{x}/{y}.png
• Mapillary Photos
• State Department of Transportation(DoT) exit number documents.
• Wikipedia
• Cross Country roads
• Aaroads

[jinalfoflia]

I came across this motorway where the user mdroads has added destination:street=* tags instead of destination=* tag. There are 1589 ways in OpenStreetMap that are tagged using this tag. There is no information about this tag in the wiki.

cc @planemad @pratikyadav

[rickmastfan67]

Maybe inviting mdroads here to comment on that tag would be the best thing to do. Especially if he has added the tag the most.

[jinalfoflia]

@rickmastfan67 I have sent a message to mdroads asking for the same.

[jinalfoflia]

Received a reply from mdroads:

The context for use of destination:street=* is to capture the street name when shown on overhead signage, destination:ref=* for the number, and destination=* only for city or place.

destination:street=* is only used when the street name actually appears on the motorway signs.

The tag is a proposal on the Exit Info wiki page, alongside destination:ref=* and some others.

This page is not well linked to the regular destination=* entry on the wiki (and should probably be merged with it), but does show North American signage tagging examples. The mostly European signage shown on the proposed Destination Details page on the other hand, rarely if ever use street names or cardinal directions.

/cc @planemad @pratikyadav @rickmastfan67

[jothirnadh]

We are adding destination:street=*, destination:ref=* and destination=* as per the availability of Mapilary and wikipedia coverage. The mapilary coverage is limited to specific highways and in such cases we are completely relying on the Wikipedia information.

It seems that the Wiki information for some highways is not correct, especially in case of highways in Texas. I was working on I-35 in Texas where there is no Mapilary coverage but a proper Wiki page with all the information related to exit numbers and destination. Here the exit numbers and the destination information were wrongly assigned which I didn't realize at the beginning and mapped the whole stretch.

An OpenStreetMap contributor got back to me pointing out the mistake by commenting on my changeset. This is a serious issue and we need to find an alternative source to map destination tags. We also need to validate the one's we mapped since last week.

cc:/ @pratikyadav @planemad @maning @lxbarth

[mikelmaron]

An OpenStreetMap contributor got back to me pointing out the mistake by commenting on my changeset. This is a serious issue and we need to find an alternative source to map destination tags. We also need to validate the one's we mapped since last week.

@jothirnadh I read the changeset comment differently. Wikipedia might be correct but you were applying the exits in Iowa, not in Texas. If so, that would explain the issue, and we should pay closer attention to where we're mapping.

[jothirnadh]

@mikelmaron you are right. This mainly happened because, checkautopista downloads all the highways in its bounding box, not limiting it to a state. I was not aware of this and started to add destination tags to all the I 35 highways it downloaded. Will keep track of things from now.

[pratikyadav]

Project Summary

In the course of 12 days, the team added 3417 destination, destination:ref and destination:street tags in 9 US states using Mapillary images, state DOT documents, Wikipedia, Cross Country roads and Inter-state guides.

Observation-

• Motorways in these states have mixed usage of both exit_to and destination tagging scheme.
• The presence of mapillary images helped a lot to add missing destination tags. The next most commonly used source was DOT documents (which are not available in every state). Wikipedia as a source was incorrect at few instances and thus, we relied more on mapillary, Cross Country roads, and inter-state guide images.
• When in doubt due to discrepancy, adding a note on OSM is the best idea.

Project Statistics-

• Avg. mappers involved: ~6
• Days spent mapping: 12
• # of highways reviewed: ~220
• # of tags added: 3417
  • destination tag added: 1663 (link to geojson)
  • destination:ref tag added: 1481 (link to geojson)
  • destination:street tag added: 273 (link to geojson)
• # of tags per hour/person: ~15

Closing here.
🚀

[rickmastfan67]

I hope you guys paid attention to signs that had the "TO" text in them beside the highway shields and properly tagged them as "destination:ref:to". Case in point: http://www.openstreetmap.org/changeset/38919762

[pratikyadav]

@rickmastfan67 Thanks you for pointing this out. We fixed this particular one and will make sure to keep an eye on these cases during our peer review session. Feel free to post any such case on these peer-review tickets.

[krishnanammala]

OSM Diary --> http://www.openstreetmap.org/user/nammala/diary/38560

[dgearhart]

I found an issue when a way is both an off ramp and an on ramp. The way will need to be split between an off ramp and an on ramp or it will produce invalid driving directions.
I documented the issue and how to fix on the Exit Info wiki so others can benefit from our discussion: http://wiki.openstreetmap.org/wiki/Exit_Info#Off_Ramp.2FOn_Ramp_Way_Split

[dgearhart]

I made a comment on this changeset: http://www.openstreetmap.org/changeset/38979964
I fixed the issues.
I would suggest doing before and after testing of routes to confirm the tagging is appropriate

[pratikyadav]

@dgearhart Thank you for bringing this up. Currently, we are working on a tool that can help scale-up the validation work for this and other projects, where we used mapillary as a source to add tags on OSM.